Sharing code for a UserControl between Metro and WPF?

That doesn't sound like a namespace issue. InitializeComponent should be part of the cs file automatically generated from the Xaml.

How did you add your user control to your project? I just confirmed that if I do "Add.New Item..." and select User Control then copy your code in it works correctly. The only code change I made was to switch App1.Shared to my namespace in both files.

--Rob